Apparatus for electrodepositing metal on bearing shells and the like



Dec. 2, 1947. w. M. MARTZ ,948

APPARATUS FOR ELECTRODEPOSITING METAL ON BEARING SHELLS AND THE LIKEFiled Nov. 1, 1943- I ll 1 Snnentof ZZZ/$212772 7%152 Gltorncg PatentedDec. 2, 1947 OFF] APPARATUS FOR ELECTROD-EBO SITING- METAL ON BEARINGSHELLS AND THE LIK-E .1

William"MFMartifIridianapolis, Ind., assignor to General Motors-Corporation;Detroit, Mich., a corporationpf"Delaware ApplicationNovembenl, 1943, Serial N'o:2 508,456:

1,.C1aim... (01. 2045-272) This, invention: relates genemn Vi any} ofelectrodepositing metals anddm'ore particularly to electrodepositinga"layer :or- 'coating 'of metalon the inside of bearing rshells: andathelike.

High'quality bearings such as employed in air-"- craft engines may bemade by electrodepositing a" layer or layers-of relatively :soft" metalor alloy having goodxantifrictional properties onto a sup port of'at'harder' and stronger metal which acts as the cathode'duringthe'plating operation; Different forms of apparatuses havebeenproposedheretofore zfor: electrodeposting-metal on the insideoiiibearing shells andsthe like. While some of thecplatingapparatusessordevices" have given satisfactoryresults and many' high quality bear:

ings produced thereby;- all ithoseapparatuses of whichi am aware are-subject toone-or'more dis advantages.

Infplatiilg bearings' and the like it is desirable to electrodeposit therelatively soft metal at a rapid-- rate requiring relatively highcurrent dnsities; Thisfactor alongwith" others makes it necessaryonadvantageous to provide a considerable amount of'agi'tation of the=plating solution, In some ap:

ingi solution td the inside surface *of the bear changingithe flowthrough'all of the other stacks-.3; inthe system; In accordanceWith'the'present in-:- ventioniby' making'iuse of :a* system including;gravity flow; a constant head is provided for each:

3: stack and the now throughzany stack-of a' lural ity of stacks may :be-changed"atxwillwithut; 51H?" fiuencing thes'rateof flow or :pressure in:any ofig. the. other 'stacks in the system.

Another)" disadvantage of some apparatuseslflxfheretgfore=empyed is thatmasking oithe hear ing backo-r shell formin'gthe cathode isnecessayr Theprocedure of applying'the masks. and removing: the 1 same after :platingis not 'only time con-t. sumingbut'the masks are acause=ofplatingsreellitjectidns -due=toplating solution being trappedin";

means may be employed either by itself or with-- meansto agitate orrotate the anode and/or cathode. .S'uch'movable'means are not requiredin thepreferred embodiment of my invention and the platingtsolutionisagitated and a'supply of fresh platingzsolution is brought continuouslyinto con tact iwith th'elinside surfaceoi the bearing shells by'simplemeans and without the meet rotary d-- vices inthe electrolyte;-

Inrgeneral: there are advantages in flo'wingth'eelectrolyte upwardlythrough a stack 0f bearings orotherzanticles tribe plated. It isdesirable also to :have positive pressure such" as provided by acorrect' type of pump. It' is desirable from pr m ticalzconsiderationsto employ a plurality of plat-= ingiunits :forieach'tankof plating "solution in or- 0"th'e outside of the bearing shells;plated-:atione time. However; unless a separateder. thatfa plurality ofstacks of bearings canbe pumpsis used for each-plating unit, it isdiflieult to :control the rate of flow through the individualstacksY-andithe rate of fiowithrough OIIG OIclIlOIE stacks cannot.ibe-salterediwithwt simultaneously #1 55 Y the'various types ofmasks-employed; In the pre-; ferred 'embodiment of my invention noexternal; masking devices are :necessary;

Che objectcitric-invention is the provisionof an improved apparatus forplating bearing shells' a and the :like thateliminates defects-indevices. heretofore employed.

Another object of the invention'is theaprovi sion'of 'an'apparatus forplating bearings and the 'like that iseharacteriz'ed 'by its simplicity"andease of operationand control.

It is also anobject of this invention to provide an apparatus" of simpleconstruction adapted te-- plate a plurality of stacks ofbearings andthe-'- like atone time and wherein theflow through any one stack may bechanged'without influencing the rate of new through any of the otherstacks":

IEisalsoanobjector this invention to provide animproved apparatus forplating aplurality of stacks of hearing and the like at one time inwhich-- onlyasingle'pump is required-to circulate-the:

platingsolution and in which the 'flow characteristics through any-onestack maybe changed without afiecting the flow characteristicsthrough-any of the other stacks.-

A further object of the invention isthe "pro-'--- vision of animproveddevice of the class'described in whichit is practical to filter theplating solutionso that only filtered solution flows past the "cathode.

It is-a further object of the invention to pro vide' an improvedapparatus for plating'thein side of bearing shells and the like thateliminates the necessity of employing-masking devices for Afurtherobject of the inventionis to'provide an improvedmeans-for maintaining afresh and undepleted' supply of plating solution at "the sur facesto beplated.

It is' 'also an object of' the invention to provide a device of theclass described in which no rotary devices are required in theelectrolyte.

'Another object of the invention is to provide a device of the classdescribed in which only a small amount of floor space is required perstack of bearings or other articles being plated.

Other objects and advantages of the invention will become more apparentfrom the detailed description which follows.

Reference is herewith made to the accompanying drawing illustrating anapparatus in accord ance with one embodiment of the invention.

In the drawing:

Figure 1 is an elevational view with parts broken away and with parts insection illustrating an apparatus in accordance with the invention.

Figure 2 is an enlarged sectional view of one of the plating unitassemblies shown in Figure 1.

In the drawing, in indicates a lower tank having a supply I2 of platingsolution or electrolyte. Directly above the lower tank is another tankIs, in which is an amount of plating solution indicated by It. For thepurpose of pumping the plating solution from the lower tank to the uppertank there are provided; a pipe I8 leading from the lower tank to theinlet side of pump 20, a pump outlet 22, a filter 24 and a pipe 26leading from the filter and discharging into the upper tank. In thebottom of the upper tank are a plurality of similar outlet tubes orpipes 28, in this case three in number. Each outlet tube has a valve 30therein wherein flow of electrolyte therein can be stopped entirely orregulated in amount. Each of the outlet tubes 28 leads downwardly to acorresponding plating unit assembly in the lower tank ind catedgenerally by 32. The plating unit assemblies each comprise a hollowsupport 33 formed of hard rubber or equivalent material, a chamber 34 ineach support, atubular connection 35 of rubber connecting the lower endof a pipe 28 and a chamber 34, an orifice plate or annular plug 35 ofhard rubber or equivalent material having openings 3'! through whichelectrolyte flows from each chamber, a soft rubber gasket 38, a bearingshell assembly including two bearing shells ll] and G2, a soft rubbergasket 44 and a metallic clamping ring 46, a cap 48 of hard rubber abovethe bearing shell assembly having inner curved portions 49 and 50, asoft rubber gasket 52 between the upper bearing shell and cap forming atight seal therebetween, and a hollow anode 54 within the bearingassembly, said anode passing downwardly through the orifice plate 36 andhard rubber support 33 and discharging into the lower tank It). Thehollow support 33 is generally cup-shaped and has a base and upwardlyextending walls of generally circular shape. The upper portion of thehollow anode is spaced from the stack of bearing shells so as to form anannular passage between the same, while the intermediate portion of thehollow anode is spaced from the upwardly extending walls of the hollowsupport shape, the two annular passages being connected together. Thelower end of the tubular'anode passes through a centrally arrangedopening in the base or bottom of the cup-shaped support and is inliquid-tight engagement therewith. The electrolyte enters the hollowsupport by means of tubular connection 35 and flows upwardly in theannular passages until it reaches the upperend of the cathode and thenflows downwardly through the tubular anode for return to the lowersupply tank. It will be understood that the anode will 'be connected tothe positive side of a source 33 to form a passage otannular- 4 ofdirect current and the metallic bearing shells 40 and 42 electricallyconnected to each other by metallic clamping ring 36 will be connectedto the negative side of the source of current to form the cathode onwhich metal will be electrodeposited in the plating operation by meansof electric current passing through the electrolyte from the anode tothe cathode.

Another pipe 56 leads from a point in the upper tank to a point ofdischarge in the lower tank and acts as an overflow return should thepump 20 circulate more solution or electrolyte to the upper tank than isreturned to the lower tank by means of the pipes or tubes 28 leading tothe several plating units.

As shown the solution in the lower tank is below the lowermost bearingshell and surrounding the hollow supports 33. When the solution level isthus maintained no external masking is required for the bearing shells.

The upper tank is supported above the lower tank at a suificient heightto give sufficient volume of flow by means of gravity flow through eachof the pipes 28 leading to the plating units. In most cases a head of 24to 30 inches gives sufficient volume of flow upwardly through theplating units. For fine adjustment the valves 30 in the pipes 28 may beoperated to control the flow. The flow through any pipe 28 may be cutoil entirely without affecting the head or amount of flow through theother pipes.

As shown the jet or orifice plate 36 has the openings 31 arrangedspirally at an angle of about 45 in order to impart a spiral flow to theelectrolyte as it passes upward between the hollow anode and bearingshells. This most effectively brings fresh platin solution into contactwith the surfaces to be plated. In some cases the orifices may be sodisposed as to cause the flow to be straight up between the anode andbearing shells.

The anodes and other materials may be whatever is necessary to conformwith the type of electrolyte. If, for example, the solution orelectrolyte is a silver plating solution, the anode may be of silver. Inthis case, of course, the anode will be used up as the silver passesinto solution during electrolysis and eventually the anode must bereplaced. If the anode is of iron or other insoluble material, it willbe necessary to replace or replenish the silver that is electrodepositedout of the electrolyte. This can be accomplished by adding a silver saltto the electrolyte from time to time, or other means may be employed.

The number of units which may be used in the tank are, of course,limited only by the size of the tank desired.

While the construction illustrated in the drawings shows only twobearing shells in each assembly, it will be understood that a greaternumber can be plated at one time at each plating unit, or, of course,only one, if desired. After the desired thickness of metal iselectrodeposited'onto each bearing shell assembly, the rubber cap 48 andgasket 52 are'removed from the upper bearing shell and the bearing shellassembly removed from its seat on the soft rubber gasket 38, whereuponan unplated bearing shell assembly can then be placed in position forplating. The operation of removing a plated bearing assembly andinserting an unplated bearing assembly is a simple one. The clamping rin46 has adjustable screws 10 which, when tightened, secure the twobearing shells together as an assembly. When the screws are loosened thebearings can be separated from each other. The electrical connectionleading to the negative side of the source of plating current may beattached to the clamping ring.

It will be understood that the soft rubber gaskets 38, 44 and 52 formliquid tight seals which prevent the electrolyte from escaping duringupward flow of the electrolytebetween the hollow anode and bearinassembly. The curved portions 49 and 50 of the caps are for the purposeof directing the electrolyte into the inside of the hollow anode with aslittle turbulence as possible. Each cap 48 forms a tight press fit withthe bearing shell. If desired, suitable clamping or hold down means (notshown) may be employed to hold the caps in position during the platingoperation.

In place of causing the electrolyte to return to the lower tank throughthe anode it is possible to omit the cap member and otherwise modify theconstruction to permit the electrolyte to flow over the upper edge ofthe upper bearing shell of the bearing shell assembly and return to thelower tank. In such case, however, suitable external masking means mustbe provided for the backs of the bearing shells. Suitable masking meansalso will be required in the apparatus illustrated in the drawing if thesolution level is permitted to rise above the portion of the bearingshell assembly above the hollow support 32.

Various changes and modifications may be made without departing from thespirit and principles of the invention.

1 claim:

An apparatus for electrodepositing metal on the inside of a stack ofbearing shells and the like which comprises, a generally cup-shapedsupport having a base and upwardly extending walls of generally circularshape, the upper portions of said walls adapted to engage in liquidtightrelation and support a stack of bearing shells connected together toform a tubular cathode, said base having an opening centrally arrangedtherein, a tubular anode having an upper portion within the tubularcathode, an intermediate portion within the cup-shaped support and alower portion extending through said opening, said upper portion beingspaced from said tubu- 6 lar cathode to form an annular passage forelectrolyte between said tubular cathode and said upper portion, saidintermediate portion being spaced from said walls and forming therewitha passage of annular shape, said annular passages thus being connectedtogether, said lower portion being in liquid-tight engagement with saidopening, an annular plug in the annular passage between saidintermediate portion and said walls at a point between said base andupper end of said walls, said plug having angularly arranged jetopenings adapted to impart a spiralling effect to electrolyte as itflows therethrough, a cap in liquid-tight engagement with the upper endof said tubular cathode and spaced from the upper end of said tubularanode, means for flowing electrolyte into said annular passage belowsaid plug, then upwardly through the angularly arranged jet openings,then spirally upward through said annular passageway formed between theupper portion of said tubular anode and said tubular cathode to theupper end of the cathode and then downwardly through the tubular anode,and means for passing electric current from the tubular anode to thetubular cathode through the electrolyte flowing spirally upward in saidannular passageway between the two.

WILLIAM M. MARTZ.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,259,683 Van Hasselt Mar. 19,1918 686,395 Dessolle Nov. 12, 1901 2,297,252 Schmidt Sept. 29, 19421,886,218 Olin Nov. 1, 1932 1,594,509 Rosenqvist Aug. 3, 1926 588,740Becker Aug. 24, 1897 1,872,290 Hitner Aug. 16, 1932 1,927,162 Fiedler etal Sept, 19, 1933 FOREIGN PATENTS Number Country Date 215,409Switzerland Nov. 3, 1939 825,071 France Nov. 27, 1937

